Valve stem oil seal



April 25, 1950 E. s. M PHERSON VALVE STEM OIL SEAL Filed Feb. 19, 1945 II l ll.

645K12 jflaetfazr Grim-nous Patented Apr. 25, 1950 2,505,128

UNITED STATES PATENT OFFICE VALVE STEM 01L SEAL Earle s. Maclherson,Detroit, Mich., asslgnor to General Motors Corporation, Detroit, Mich.,a corporation of Delaware Application February 19, 1945, Serial No.578,778

:= Claims. (Cl. 251-144) A problem has arisen in connection with thelubrication of the rocker arms for operating the valves of engines. Someof the oil supplied for the rocker arm bearing reaches the end of thevalve and flows down the stem through the guide and thus reaches theentrance to the combustion chamber.

To avoid this flow of oil down the valve stem and through the valveguide resort has been had provision for preventing this flow of oil isbest seen in Figures 2- and 3. The valve stem has a circumferentialgroove indicated by numeral 31. A split key marked 39 is placed withinthis groove. Its halves have flared peripheries which, when assembled,form a cone having its greater diameter adjacent the end of the stem.The groove is of such axial length that beneath the key there may befitted into the lower end of the groove a to asort of umbrella coveringthe top of the valve ring of synthetic rubber 4| or other deformablestem. While this has been productive of good rematerial. This rubberwhen assembled may be suits, the inertia of such an added metal platesubstantially circularin cross section. The spring interferes, to someextent, with the operation of abutment 29 is in the form of a, taperedsleeve the valve. 43 having its larger diameter uppermost, and a Thepresent invention has for its object the flange 45 which is hollowed outto receive the end same prevention of a flow of oil down the valve stemand it proposes to accomplish its object without materially augmentingtheinertia effects. Other objects such as simplicity in construction,eiilciency in operation and low cost will be understood from thedescription which follows.

In the accompanyin r wing:

Fig. 1 is a view in section through the upper end of an engine and itshead with the novel oil seal shown on the valve stem.

Fig. 2 'is a sectional view of the oil seal on a larger scale.

Fig. 3 is a wiew in perspective of two parts in disassembled relation.

Referring by reference characters to the drawing, the cylinder is marked5' and its piston I. The head 9 forms, together with the cylinder, a

of the spring 21. As the spring moves the abutment plate upwardly thecooperating inclined faces of its sleeve and of the key limit the up-'ward movement, the key being pressed into the groove of the stem as itdetermines the operative position of the abutment.

It will be seen from the drawing that the inner diameter of the lowerend of sleeve 43 is less than the outer diameter of the seal 4|. As theabutment reaches its operative position it therefore deforms the sealsomewhat as shown by Fig. 2. In consequence, any oil around the end ofthe stem is sealed from flowing down the stem and through the guide. Theexpedient accomplishes its purpose without adding materially to theweight and consequently to the inertia effects which were present ininstallations where metal combustion chamber ll within which theexploplates were used to shed the oil. sion occurs when the chargetherein is fired by I claim: the spark plug it. 1. A valve having astem, a circumferential Valves l5 and I! control the inlet of theexplosive mixture and the discharge of burned gases as usual. They haveheads as seen at I! to open and close the passages such as 2| leading tothe recess adjacent the top of the stem having a non-tapered portion andanother portion, a split ring key seated in the non-tapered portion ofsaid groove and having a tapered external surchamber l I. The valvestems 23 slide through face, a spring abutment with a tapered boreenguides 25 as usual. A spring 21 is seated on a gaging the taperedexternal surface of said key surface of the cylinder head and pressesagainst to secure the abutment to the stem, a. deforman abutment 29carried by the end of the stem able incompressible ring of greatercross-section thus serving as the means to close the valve. A than saidrecess seated in the other portion of rocker arm 3| for each valve isrotatably supsaid recess and also in contact with the bottom ported at33 in the usual way. One end is pushed surface of said key and saidtapered bore, said by a push rod '35 actuated by the engine camtaperedbore at the lower edge of said ring being shaft, not shown, and theother end pushes against of substantially larger diameter than said stemthe valve stem. It intermittently serves to overand being open belowsaid ring to provide a space come the pressure of the spring and openthe between the spring abutment and the stem to valve.

With this arrangement of valve operation, oil 7 down within the guidewith harmful results. The

accommodate axial deformation of said ring when it is compressed betweenthe stem and the tapered bore of the spring abutment for sealing so thatthe abutment will seat properly on the key.

' 3 2. A valvehaving a stem as defined in claim -1 in which said otherportion of said recess is a smooth curve so that the rins will not becut when deformed.

3. A valve having a stem, stop means on said stem, interengaging meanson said stem and stop means to position said stop means on the stem, aspring abutment having a central aperture, interengaging means on saidstop means and spring abutment for securing the abutment and stemtogether in substantially concentric relation, the apertured portion ofsaid spring abutment extending beyond said stop means and surroundingsaid stem in spaced relation to provide an annular space which is openedat one side with the stem constituting the inner wall and the springabutment the outer wall, said space including an annular recess in oneof said walls, a resilient deformable substantially incompressiblerubberlike ring positioned in the portion of said annular spaceincluding said recess and contacting the otherwall, said ring beingdeformed by said walls to have a diametral thickness the same as thedistance between said other wall and the base of said recess and toincrease its depth in said annular space, and said open side providingan outlet for the flow of the excess of the deformed ring.

4. A valve having a stem, stop means on said stem, said stop meanshaving a. face around said stem, a spring abutment having a centraltapered aperture, said spring abutment and said stop means engaging eachother to secure the abutment to the stem, a deformable incompressiblering surrounding said stem and occupying an annular space of less radialthickness than said ring and bounded internally by the stem, externallyby the tapered aperture and at one side by said face, the minimumdiameter of said tapered aperture being larger than the diameter of saidstem at the other side of the ring whereby said space extends beyondsaid ring to provide 4 space between the spring abutment and the stem toaccommodate axial deformation of the ring when it is compressed betweenthe stem and tapered aperture of the spring abutment for sealing so thatthe abutment will seat properly on the stop means.

5. A valve having a stem, stop means on said stem. said stop meanshaving a face around said stem, a spring abutment having a centralaperture, said spring abutment and said stop means having interengagingmeans to substantially concentrically secure the abutment to the stem,at deformable incompressible ring surrounding said stem and occupying aportion of an annular space of less radial thickness than said ring,bounded internally by the stem, externally by the aperture, and at oneside by said stop means, the diameter of said aperture at the other sideof the ring being larger than the diameter of said stem at said otherside of the ring whereby said space is open beyond said ring to providespace around said stem to accommodate axial deformation of the ring whenit is compressed between the stem and aperture of the spring abutmentfor sealing so that the abutment will seat properly on the stop means.

EARLE S. MAcPHERSON.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 940,143 Foltz Nov. 16, 19001,344,347 Lee June 22, 1020 1,370,346 Nelson Mar. 1, 1025'. 1,420,898Willey June 27, 1922 1,482,774 Wills Feb. 4, 1924 1,711,267 Hutt Apr.30, 1929 2,330,091 Townhill Sept. 21, 1943

